The existence of antigonadotropins or hormones that inhibit egg development, oostatic hormones, has been demonstrated in the cockroach, eye gnat, crustaceans, house fly, and mosquitoes (Borovsky, D. [1985], Arch. Insect Biochem. Physiol. 2:333-349). To our knowledge, no substance has been purified to homogeneity, identified and synthesized and shown to have a dose response effect inhibiting egg development and proteolytic enzyme biosynthesis against flies, sand flies, Culicoides, cat fleas and different species of mosquitoes.
Borovsky, D. (1985), Arch. Ins. Biochem. Physiol. 2:333-349 has purified the hormone 7,000-fold and disclosed that injection of a hormone preparation into the body cavity of blood imbibed insects caused inhibition of egg development and sterility in insects. Following these observations Borovsky, D. (1988), Arch. Ins. Biochem. Physiol. 7:187-210 disclosed that injection or passage of a peptide hormone preparation into blood sucking insects caused inhibition in the biosynthesis of serine esterase, trypsinlike and chymotrypsinlike enzymes biosynthesis in the epithelium cells of the gut. Since trypsin is the major proteolytic enzyme synthesized in this insect (about 70-80%), the blood meal is not digested efficiently, and consequently free amino acids needed for the synthesis of the yolk protein synthesis in the fat body are not released into the hemolymph, yolk protein is not synthesized and yolk is not deposited in the ovaries, and egg development is arrested.
The rapid increase in pesticide resistance of disease-borne arthropods makes our hormonal approach a safer alternative to the chemical approach (e.g., synthetic pyrethroid, organochlorine, and organophosphates).